Electro-iviagnetic regulator for contact-telephones



(No Mode-U I W. L. VOELKER. El eotro-Magnetio, Regulator f-o'r Contact. Telephones.

No. 231,738. Patented 'Aug. 31,1880.

I F l.

Nrrn STATES Fries.

ATENT WILLIAM L. VOELKER, OF MORTON, PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 231,738, dated August 31, 1880. Application filed May 4, 1880. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM L. VonLKER, of Morton, in the county of Delaware and State of Pennsylvania, have invented a new and useful Electro-llfagnetic Regulator for (Jontaot-Electrodes in a Telephone; and I do hereby declare that the following is a full and complete description of the same.

This invention relates to that class of telephones for which several Letters Patent have been granted to John H. Irwin, wherein the contact oftwo separate electrodes, one or both, being made pointed, presents at the place of contact a smaller cross-sectional area than the cross-section of the conductor in the batterycircuit.

In telephones having electrodes of this character the pointed electrode will slightly embed itself in the opposite electrode, especially when the one is of hard and refractory platinum, and the other of gascarbon or its equivalent.

The electrical current in passingthis pointof attenuation in the conductor meets with resistance by reason of this attenuation, as is well known in electrical conductors, and as one or bot-h of the electrodes move in obedience to the vibrations of the impacting sound-waves, they can only move as to each other on a coinciding axial line, and it follows that every such movement increases or diminishes the atten nation of the conductor at the contact-point, according as the movement is in recession or advance, and as said attenuation is varied the resistance is varied also.

If the reproduction of the initial sounds in the receiver requires that the electrical impulses, both as to their initial amplitude and as to their intervals of succession, shall be transmitted to the receiver, it appears evident that varying quantities of electricity will give relativelyvarying amplitudes to those impulses unless compensated in some way, because with a uniform resistance a larger percentage will pass said resistance if the current is weak than if it is strong. And it follows, therefore, that the resistance ought to be graduated to the quantity of electricity in the conductor in order to obtain relative uniformity in electrical impulses. I therefore increase the lninish it when the current is resistance when the current is weak, and distrong.

The object of my present invention is to accom plish this result automatically; and it consists in an electro-magnet in the transmittercircuit arranged with suitable armatures and connected to the electrodes, so that when the battery-current is strong said magnet will be strongly excited and will draw the electrodes more strongly into contact, and when the current is weaker said magnets will correspondin gly relax, and permit an adjustable differentiating retracting force to diminish the electrode contact.

Having now set forth the nature of my invention, I will particularly describe a practical method of construction, having reference to the accompanying drawings, wherein- Figure 1 is a perspective View of my instrument. Fig. 2 is a vertical section of-the same.

A is the base or frame of the instrument, made in any proper manner. B is one of the electrodes, which is usually of carbon. C is the opposite electrode, usually a needle-point of platinum mounted upon or suspended from a differentiating-spring, D. The spring D is supplied witha device, E, or its equivalent, for regulating or adjusting the tension of the spring D and the initial contact between the electrodes. This adjustment must be made with reference to the strength of the batterycurrent, and can only be obtained by experiment.

In the drawings, the needle 0 is shown as suspended by a delicate coiled spring, D; but

atlatorother form of spring maybe employed, and I do not limit myself herein to the kind or form of spring which may be employed.

The spring D tends to separate the electrodes; but-its tension is adjusted so that it will regulate the contact and adjust it to the proper extent, as indicated by experiment. This, however, has been done before, and my invention supplements this elastic regulation with an opposite electromagnetic force, which tends to bring the electrodes together, and which is also differentiated by the spring D, so that as the battery-current varies in quantity the electrode contact will correspondingly vary, as hereinbefore set forth.

The electro-mztgnet is shown at F, and its tro-mztgnet F in the battery-circuit, and an adarmztture G is attached to the electrode 0. jnstable differentiating spring, I), snbstan- 10 The battery-circuit Wire H also forms the pritieiiy as set forth.

mary of the electro-n agnets F F. WILLIAM L VOELKER 5 Having described my invention, What I claim as new is- Witnesses:

The needle-pointed electrode 0, provided KINGSTON GODDARD, with an armature, G, combined with the elec- 'F. A. WAIT. 

